If you think colored newsprint is bad, wait until you learn of how white paper towels are made. Mmmm tasty dioxides
In honesty your ball python is not going to eat paper unless it is finely shredded and they consume some with food. This goes for any paper product really. If you really want to have piece of mind just get non bleached brown paper or unprinted news print as both are readily available. Things like seventh generation products are an example of non bleached paper towels.